Grinding and polishing machine.



J. G. BLEVNEY.

GRINDING AND POLISHING MACHINE. APPLICATION FILED NOV. 27, 1911.

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Patented Nov. 5, 1912.

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GRINDING AND POLISHING MAGHIN.

APPLICATION FILED NOV. 27, 1911.

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Patented Nov. 5

J. C. BLEVNEY.

| l l 1 I l l l Ilrllllllll I |lLll||||||||||ll| GRINDING AND POLISHING MACHINE.

APPLICATION FILED Nov. 27, 1911` www@ J. C. BLEVNBY.

GRINDING AND POLISHING MACHINE.

APPLIOATION FILED Nov. 27, 1911.

1,043,194. Patnted N0v.5,1912.

ATTORNEYS en carica.

JOHNiC.- BIEVNEY, 0F NEWARK, NEW JERSEY.

' iG'R'Ilil'IIJIlG AND POLISHING MACHINE.

Specification of Letters Patent. j

rammen Nov. 5, i912.

Application led november 27, 19M. Serial No. $62,532.

To all whom it may concern:

Be it known that l, JOHN C. BLEvNnY, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new .and useful Improvements in Grinding and Polishing Machines; and I do hereby' declare the following to be a full, clear, and exact description ot' the invention, such as will enable others skilled in the art towhich it appertains to make and` use the same, reference being had to the accompanying drawings, and to characters of reference marked thereon, which.VJ form a partof this specification.

This invention has reference, generally,

to improvements in grinding and polishing machinery.

The present invention has for its principal object to .provide an eiicient apparatus for grinding and polishing objects having l two or more flat surfaces, such for example as square, or other 4polygonally-shaped rods or tubing; and, it is the purpose of the machine `to provide such objects with a smooth, uniform, and highly finished surface, free from blemishes, burns, or buckling appearance.

Tn addition to this object, the present invcnti'onprovidcs a quick and eiiicient means for handling and controlling the movements of the objects to be ground or polished, s0 that the same may be properly and com- I pletely treated by the grinding and polishing elements of the machine.

The various specific objects of the present invention, not at this time more particularly enumerated, will be clearly understood from the following detailed description of this invention.

With the various objects of the present invention in view, the said .invention consists, primarily, in the novel grinding and polishing machine hereinafter set forth; and, the invention consists, furthermore, in the novel arrangements and combinations of the several devices and parts, as well as in the details of the construction ofthe same, all

of which will be more fully described in the following specification, and then finallyembodied in the'cnuses Aof the Claims which i are appended to and which form an essen- 3, looking in the direction of the arrow m;

Fig. 5 is a detail side elevation and part longitudinal vertical section of a gravity presser-foot, made on an enlarged scale, and V removed from its connection with the machine, the same being adapted to press the grinding element or beltegainst the material or objects vto beworked upon; and Fig. 6 is a transverse vertical section of the same, said section being taken on line 6--6 in said Fig. 5. Fig. 7 is a large detail plan view of a portion of the feeding element or belt,l showing in connection therewith, the

means of attaching or connecting the ob-'.

jects to be polished or ground thereupon; Fig. 8 is a detail longitudinal vertical sec- Fig. 7 and Fig. 9 is a detail vertical longitudinal section of a means for adjusting the tension of the feed-belt of the apparatus.

Similar characters of reference are employed in all of the above described views,

to indicate corresponding parts.

Referring now to the said drawings, the reference-character 1- indicates the frame of the machine, and 2 indicates the main driving shaft which is suitably supported in bearings in the upper portion of said frame.

. tion of the same, takenon line 8-8 in said v which are respectively supported suitable adjustable bearing-brackets 7 and 7a which carry the respective shaftsv 8 and 8a upon which are rotatably mounted the pulleywheels 9 and 9a.

The reference-character 10 indicates a suitable cushion-belt which is provided upon vide a bearing for a hollow screw-threaded standard 13, the lower end of which is provided with a suitable hand-wheel 14, for the proper manipulation of the same. The reference character 15 indicates a suitable table-beam bracket having an offset-member 16 to which is secured a table-beam 17, in such a manner, so as to provide a free space beneath the latter. Extending downwardly from said bracket 15 is a cylindrical shank 15 which is mounted so as to slide vertically within said hollow screw-threaded standard 13, and suitably secured upon said shank 15 is a split collar 15b, against which the upper face-end yof' said hollow screw-threaded standard 13 bears, so as to support said bracket 15 in such a manner, that it is capable of a slight vertical movement, limited,

' however, in its downward direction by the stop aorded by said hollow screw-threaded standard 13. The rough vertical adjustments of the su porting position of said table-beam-brac et 15 may be secured by movingthe said split collar 15b up or down upon said shank 15, and the finer adjustments may then be made by raising or lowerin said hollow-screw-threaded standard 13, y turnin the hand wheel 14. Said table-beam 17 1s provided with transversely and horizontally extending supporting ariusI 18 which are formed with suitable bedbrackets 19, each bracket having a air of downwardly extending portions 20, t e free ends of which form bearings which'are slidably connected or arranged upon the respective supporting arms 18. Suitably supported by means of said. respective bed-brackets' 19 is a longitudinally extending work-supporting' table 21, which is arranged in such a manner, so that it extends beneath the said grinding belt 11, where the latter is presented in its grinding position. Secured at one` end of said wor -supporting table 21 is a bracket-member 22 which is provided with a pair of bearing-portions 23 in whichlisjournaled a driven. shaft 24, upon which is suitably mounted a feed-belt pulley 25. Secured at the opposite end of said work-supporting table 21 is an adjustable bracketmember 26 which is' also provided with bearing-portions 27 in which is mounted a shaft 28, said shaft 28 having mounted thereon an idler-pulley 29. The reference-character 30 indicates4 a feed-belt which passes around the said feed-belt pulley 25, and extends longitudinally above said table in alinement with said grindingbelt 11 and beneath the same, and then passes over said idler-pulley 29 and returns beneath said work-supporting table, and table-beam, through the free space between the said table-beam 17 and saiddtable-beam-bracket 15, the latter being provided with arms 15c upon -which are mounted anti-friction rollers 15d upon which said returning portion ofthe feed-belt 30 rides. The purpose of mounting said bracket-member 26 adjustably in connection with said table 21 is to providea means for carrying said idler-pulley 29 in armanner to permit of adjusting the tension of the said feed-belt 30. To this end,|said adjustable bracket 26 is provided with a tail-piece 26 which is slidably mounted so as' to move inwardly or outwardly in a track-piece 26b which is secured to the under surface of said table 21.l Said tail-piece 26Ael is provided upon its upper surface with a ratchet or a series of serrations 26r arranged so as to be engaged by a pivotal y mounted pawl 26d which is suitably connected with said trackpiece 26". The pull of said feed-belt pulls said ratchet 26 against said pawl, whereby said bracket-memberl is held in its adjusted position to produce the desired tension of said feed-belt 30, in a manner clearly to be understood from aninspection of Fig. 9 of the accompanying drawings. Said pawl 26d may be provided with a nger-piece 26 which may be manipulated through the opening 26 in the `table 21 in which said pawl lies, so that the same vmay be quickly released from its holding engagement with said ratchet, to allow said bracket-member 26 to be moved inwardly to any desired position. The reference-character 31 indicates a pulley which is secured upon said main driving shaft 2 and `'over which -runs a belt 32 for driving a larger pulley 33 which is secured upon a counter-shaft 34, and which shaft is journaled in suitable bearings .in the lower portion ofthe. frame 1. Suitably connected with eaid'iflrame f1 Sis an outwardly extending arinil upon which is secured, in any desired position, andiis capable of longitudinal .adjustment thereon, a bearingmember 36 in which isfadjustably 'ournaled a counter-shaft'37, u on' one end o which is xed a pulley 38. ounted -u on the said counter-shaft 34 is asmall p ley 39V over which runs a be1t40, by means of whichv the said pulley 38 and counter-shaft 37 are driven. i

The reference-character 41 indicates a transversely arranged shaft which is journaled in a bearing-member 42 connected with the previously mentionedv table-beam,

and 43 indicatesv a transmission shaft which operates between the said counter-shaft 37 and the said transverse shaft 41. Operatively connecting the said counter-shaft 37 with said transmission shaft 43 is an incased set of intermeshing bevel gears 44, the members of which are respectively connected with said counter-shaft 37 and said transmission shaft 43, whereby the movement or rotation of the former is transmitted to the latter. In like manner, operatively connecting said transmission shaft 43 with said transverse shaft l41 is an incased set of intermeshing bevel gears 45, the members of which are respectively connected with said transmission shaft 43 and said transverse shaft 41, whereby the movement o-r rotation of the former is, in turn, transmitted to the latter, all of which willV be clearly evident from an inspection of the several figures of the drawings.

It is desirable that the work-supporting table 21 shall have a transverse reciprocatory movement during the operation ofthe machine, to the end, that the work to be gro-und or polished may be carried'in contact.- transversely with all portions of the grinding belt l1, so that the entire grinding efficiency of the belt may be utilized, and the same prevented from streaking or wearing oif in limited portions of its grinding surface, instead `of being uniformlyand evenly worn oil". To accomplish this result, there is provided a longitudinally extending rock-shaft 46 which is supported by means of shaft-hangers 47, depending from portions of said supporting arms 18 ofthe ltable-beam 17. Secured in proper locations upon said rock-shaft 46 are suitable leverarms 48, said lever-arms being pivotally connected with the bed-brackets 19, by means of connecting rods 49. 'Fixed `upon said rock-shaft46 is a rocker-arm 50 which is provided with an anti-friction roller 51, said roller being in operative engagement with the cam-surface 52 of a rotating cam-wheel 53, which is affixed to and is rotated by I means of said transverse shaft 41. The rotation f the said cam-Wheel 53 tends to reciprocate said rocker-arm 50, so as to oscillate tli'said rock-shaft 46 and lever-arms 48, and, the latter operatingr through said connecting rods 49, slide the said bed-brackets 19 back and forth upon said supporting arms 18, and consequently reciprocate the rock-supporting table 21 in transverse directions. Secured to said rock-shaft 46 is an outwardly extending arm 54 which is providedwith a counter-balance or weight 55, which tends to maintain said rocker-arm v 50 and its anti-friction roller 51 in constant assists in producing the reciprocatory movev ments of said Work-supporting table, as will be clearly understood. Connected with said transverse shaft 41 is a variable speed or step-pulleyV 56 over which runs a belt 57 whichI rotates another variable speed or steppulley 58, said pulley 58 being fixed upon, one end ofV a transverse counter-shaft 5,93`

journaled beneath said work-supporting table 21. Connected with the opposite end of said transverse vcounter-shaft is a pulleywheel 60 over which runs a belt 61 adapted for the purpose of driving another pulley wheel 62 which is secured toV said driven shaft 24, and by means .of-Which lthe' latter is caused to rotate said `feed-belt pulley 25 and thereby drive said feedbelt 30. The said Work-supporting table 21 is provided with means for backing or supporting the said feed-belt 30 at the point where the same presents the objects carried thereby Vto the action of thel grinding belt 11, so that said feed-belt is not permitted to yield under the pressure of said grinding-belt upon the objects to be ground or polished; but rather,

Said feed-belt is compelled to hold or press the said objects unresistingly against said grinding belt. This feed-belt backing or supporting means comprises a pair of'baseplates 63, registering longitudinally beneath the marginal edges of said feed-belt, and Supported upon said base-plates 63 are suitable 'side-langes 64, the upper marginal edges of which Vare parallel to the feed-belt and extend slightly above the upper surface of said belt, said ianges providing suitable guides between which the said feed-belt runs. Longitudinally disposed between the said base-plates and their side-flanges are a plurality of backing-members 65, said members comprising longitudinal' strips, the lower edges of which are supported upon said work-supporting table, and the upper edges of said strips being presented against the under side'of said feed-belt in supporting or backing relation thereto. Said backingmembers 65 are suitably spaced apart, to provide intervening spaces nsuitably formed spreader-blocks 67 being intermediately disposed between said members 65. Said baseplates 63, side-fianges 64, backing-members 65, and their spreader-blocks 67, are all bound together, in their operative relation, by means 'of suitably constructed and transversely extending tie-bolts G8. v .The body of said feed-belt 3() is provided with a plurality of-suit-ably disposed and staggered elongated openings or perforations 69, which are positioned in such a manner, that, as the such objects, as lengths of square rods or tubing, or rods or tubing of rectangular or other polygonal cross-section. I have, therefore, represented a pluralityof lengths of square tubing, indicated bv the reference numeral 70, disposed upon said feed-belt 80,

so as to be carried thereby beneath said grinding belt ll. Said grinding belt is arranged to run in such amanner, that its abrading surface travels in the same direction as the work carried by said feed-belt, butat a little faster speed. When the work, therefore, is carried in contact with the running abrading surface of the grinding belt, the contact is apt to cause the work to slip ahead upon said feed-belt, faster than said feed-belt is arranged to carry the same, and to the detriment of the proper action of the abrading surface upon the work. lIt is therefore necessary, to provide means to prevent the tubing 70 from slipping forward upon said feed-belt when submitted thereby to the action of said grinding-belt; and, for 'this purpose, the holding member hereinabove mentioned is provided. Said holding member comprises a loop-portion 71 which is adapted to extend into the forward open endof said tubing 70, and, extending downwardly from said loop-portion is a stop-piece 72 adapted to be inserted in one of said openings or perforations v69 of the feed belt, so as to be engaged by said feedbelt, and thus afford a stop for preventing the' tubing from sliding forward upon said feed-belt, or moving faster than said feedbelt is'arranged to carry the same. Connected with said loop-portion 71, and extending forwardly thereof, is a Hat'loop 73 which lies in the plane of said feed-belt, so as to restupon the surface thereof in a manner adapted to prevent said tubing from tipping or otherwise slipping said stop-piece 7 2 out of its proper engagement with the perforation 69 of the feed-belt. The said Astoppieces 72 project beneath the under surface of the feed-belt, so as to be engaged by the surface of said idler-pulley 29 which, upon such contact, pushes said stop-pieces out of the perforations 69, and prevents the tubes from being tipped upwardly when the feedbelt travels around the idler-pulley, and whereby said tubing is released from any positive connection with the feed-belt and is free to be delivered therefrom to a receiving table, conveyer, or other means for receiving the finished tubing. Connected wlth the respective opposite ends of said work-supporting table 2l are counter-balancing mechanisms for maintaining the balance of the table in its horizontal plane, and a proper vertical play or movement of the same .is permitted by the sliding connection of the shank l5*l witlrthe herein-above screw-threaded standard 1,3. By such means, the work-supporting table and its feed-belt may be said to be floating, so that, when uneven spots in the tubing are met with and as the same contact with said grinding belt 11, said table will yield sufciently to prevent too much pressure of the abrading surface upon said tubing, thus preventing burns or blisters, and improp-y erly ground or polished spots -to appear upon the tubing. Such floating relation of the table and its feed-belt is particularly essential when grinding or polishing tubing covered with a veneer of thin metal, such as brass-veneered iron. ,tubing which is used in manufacturing beds, and which it is desired to provide with a very highly polished finish. Each counter-balancing mechanism comprises a yoke-piece 74, connected at the under side of said work-supporting table,

the same being curved around'to provide a 95 free space for the return-portion of said running feed-belt. Connected with the lower arm of said yoke-piece 74 is a downwardly depending link-piece 7 5 which is provided at its lower end with a hook-member 76 for pivotally engaging the eye of one end of a lever-arm 77 in such a manner, so

as to allow not only the pivotal movement of said lever-arm 77, but also to allow a pivotal movement of said link-piece 75 at right angles thereto, -which is made necessary by reason of the transverse reciprocation of said work-supporting table, as above described. Said lever-arm 77 is fulcrumed in a suitable bearing-standard 7 8. Secured upon the free end of said lever-arm 77 is a counter-balance or weight 79, the same being adjustable with relation to its distance from the fulcrum ofsaid lever-arm, vso that a proper degree of balancing force may be applied to properly support said table in its so-called floating condition.

The reference-character 80 indicates theV supporting frame-work of a gravity presserfoot mechanism which is connected with the arm 6 of the machine-frame. l, so as to present said presser-foot mechanism abovethe said superimposed belts 10 and 11, at a point where the grinding belt comes in contact with the work to be ground. The object of said presser-foot is to yieldingly press said grinding belt against the work, and thus assure the eiicient operation of the abrading surface thereof upon the work to be ground. Said presser-foot comprises a rectangular frame 81 which is provided upon its longitudinal sides with a plurality of outwardly projecting studs '82, said studs riding in properly disposed slots 83, with which said frame-work 80 is provided. Pivotall y connected with said rectangular frame 8l, b v means of their side-arms 84, are a plurality of transversely extending presserweights 85, the same being provided at their upper outer ends with outwardly projecting lugs or studs l8G, which engage the upper edges ofy the longitudinal side-pieces of said rectangular frame 81, and serve to limit the downward movements of vsaid presserweights 85. Said frame 81 `is arranged and supported in such a manner, in its relation with ,the frame-work 80, that the samemay be lifted to raise said presser-weights from their operative contactiwith the belts 10 and Il. To this end, there is provided a shaft 87, having eccentric or `cam-shaped portions 88 which are journaled in a suitable manner in the upper portion of said frame-work 80, and connecting said shaft 87 with a pair of opposite studs 82 of said rectangular frame are a pair of supporting links '89. A handle-member 90 is secured to said shaft 87, by means of which the-same may loe rotated. Upon rotating said shaft 17the eccentric or cam-shaped portions tend to raise the shaft, such upward .movement being transmitted to said rectangular frame 81 by means of the said supporting links 89, said rectangular i'ramebeing guided in its vertical movements by the studs 82 which ride in` the slots 83 of said frame-work 80andy said presser-weights being prevented from swinging out of said rectangular frame 81 when the same is s0 raised, by means of the engagement of the lugs or studs 86 coming in engagement with thelatter. It will be apparent, that when said retangular frame 8l is lowered to its operative position, the said presser-weights 85v are carried downwardly until their lower edges are' brought in contact with said belts 10 and l1, and

- the samefbeing each independently pivoted to said frame, they each extend transversely in engagement with said belts, and each eX- ert, by reason of the gravitation of said weights, a yielding pressure upon all portions of thebelts passing thereunder, so that said grinding. belt is caused to bear properly and firmly upon the'iatcsurfaces ofthe tubing 7 O presented to the action of said grinding belt, as the same is carried Jforward into contact therewith by said feed-belt.

It will be understood, that veneered tubes, such as are used for bedsteads, comprise a tu-bular base upon which is imposed a very thin sheet of brass forming the veneer. In such tubes, irregular spots, higher than the v general surface of the tube .will appear, and

if too much grinding pressure is brought to bear upon such spots or irregularities, blisters will occur, or the veneer may be ruptured or broken through. For this reason, the machine must operate in such a manner that the pressure of the grinding belt is automatically regulated, so that it will bear uniformly upon all portions of the surface of the tube passing beneath the same. Such uniform pressure of the grinding belt is accomplished through the balanced floating arrangement of the work-supporting table coperatingwith Athe action of the gravity presser-foot upon the grinding belt, since, if an irregular or-high spot in the tube is met with, the balanced table yields slightly, and the grinding belt is pressed downwardly by the presser-weights of said gravity presserfoot, so that the grinding b elt tends to follow their yielding movement. The tension, however, of the grinding-belt, which is driven at a fixed speed, tends to overcome the Adownward pressure of said presserweights, when the same seek 'to press the grinding belt too far out of its normal path of movement; hence, the excess of grinding pressure, such as would exist if the work was not permitted to yield, as a high spot is presented, is obviated, and thegrinding pressure is equalized instead. h

It willbe clearly evident, that the abraduling surface of the grinding belt 11 can only act upon one side of the rectangular tubin 1r hence, the same must be passed beneath the saidv grinding belt as many times as it possesses sides `or surfaces 'to be treated. In order to make the machine completeand to facilitate the hand'lingof the tubing by the operator, lneans'for quickly returning the partially ground or treated tubing to the point where the same may be again placedupon said feed-belt 30, is provided, so as to again be carried beneath the grinding belt 11. This means comprises a return-conveyer mechanism consisting of a. pair of side-frames 91, said frames having at their forwardends suitable bearing-portions 92 which are adapted to straddle one end of saiddriven shaft 24, in order to support the said side-frames 91 at one end.

The opposite ends of said side-frames 91 are supported by the cross-bar 93 of the yoke-piece 94 of a `suitable stan-dard 95. Connected with said driven shaft 24, so as to be rotated thereby, is a pulley wheel 96, and vjournaled in said side-frames 91, so as to extendl transversely therebetween and throughout their lengths, are a plurality of idler-rollers 97 over which runs 'a-conveyer-belt 98. The pair of idler-rollers at the extreme forward ends, of said side-frames are suitably spaced with reference to each other, so that they press the said conVeyer-belt 98, as it runs over the same, against the upper side of said rotating pulley-wheel 96, thereby permitting the said pulley-wheel 96' to impart motion to said conveyer-belt 98 in the direction opposite to the direction of movement of said feed-belt 20. The said idler-rollers support the carrying-portion of said conveyerbelt in a' horlzontal plane, and in -a proper position to carry or convey the tubing placed' thereon. As the tubing 70 passes away from contact with said grinding-belt 11, it is removed from said feed-belt 30, and is then placed upon said conveyer-belt- 98 which conveys the tubing back to the starting point, whereupon the operator takes the tubing'and again places it upon the feed-belt 30, so that another side thereof is presented to the action of the grinding belt. -These operations are repeated until all sides of the tubing have been subjected to the action of the grinding belt.

The operation ofthe herein-above specified and novel construction of grinding and polishing machine, and its various parts,

. in the performance of its functions, will be fall therebetween.

readily understood froml the. foregoing specification, and an inspection of the accompanying drawings, without the neces- 'sity of further description.

As many changes may be made in the herein-above described construction of my invention and its detail parts, and many apparently widely different embodiments of my invention could be made without de, parting from the scope thereof, I intend that all matter contained in the above description, or shown in the accompanying drawings, shall 'be interpreted as illustrative and not in a limiting sense. I desire it alsoto be understood, that the language used in the following claims is intended to cover all generic and specific features of the invent-ion herein described, and all statements of the sco e of the invention, which, as a matter of anguage, might be said to I-Ience, I do not limit my present invention to ,the exact'arrangements and combinations of the devices and parts, as described in the said specification, nor do I conne myself to the exact details of the construction of the said arts, as illustrated in the accompanying raw- I claim 1. In a device of the class described, an abradin means, a work-supporting table arrange beneath the same, a feed-belt mounted in connection with said table for ,abrading means, a transversely reciprocating work-supporting table arranged beneath th'e same, means for supporting said ,Play

of the same, a feed-belt mounted in connection with said table for feeding the workv to said abrading means, means for driving said feed-belt, and a counter-balancing mechanism connected with each end of said table to balance the same in its vert-ical movements.

3.` In a device of the class described, an abrading means, a work-sup orting table arranged beneath the same, al eed-belt mounted in connection with said table for feeding the work. to said abrading means, means connected with said table for backing or supporting said feed-belt as it passes beneath said abrading means, and means for driving said feed-belt. p

4. In a device of the class described, an abrading means, a work-sup orting table arranged eneath the same, a eed-belt mounted in connection with said table for feeding the work to said abrading means,'means for driving said feed-belt, a holding member adapted tobe connectedwith said feed-belt, and a backing means provided with spaces for the free passage of said holding member, said backing. means being arranged upon said table so as to support said feedbelt as it passes beneath said abrading means.

5. In a device of the class described, an abrading means, a work-sup orting'table arranged beneath the same, a eed-belt mounted in connection with said table for feeding the work to said abrading means, said feedbeltv being provided with a plurality of perforations, a holding member adapted to engage said feed-belt by insertion inone'of said perforations, said holding member being adapted to engage the work to prevent the same from slippin forward upon said feedbelt when engage by said abrading means, and means for driving said feed-belt.

6. In a device of t-he class described, an abrading means, -a work-supportingtable arranged beneath the same, said table having a balanced vertical movement, means for transversely reci rocating said work-supporting table, a eed-belt mounted in connection with said table for feeding the Work t0 said abrading means, means connected with said table for backing said feed-belt as it passes beneath said abrading means, va holding member adapted to engage both said feed-belt and the work to prevent the latter fromslipping forward upon said feed-belt when engaged by said abradin means, and means for driving said feed-beIt.

7. In a device of theclass described, an abrading means, a work-supporting table arranged beneath the same, said table having a balanced -vertical movement, means for transversely reciprocating said work-supporting table, a feed-belt mounted in connection with said table for feeding the work to said abrading means, means `connected .ed in connection with said table for feeding the work to said abrading means, means for driving said feed-belt, a backing means con- 'nected with said table for supporting said feed-belt as it passes beneath said abrading means, comprising a plurality of longitudinally extending backingP members arranged to provide intervening spaces, and means for supporting said backing members, said feedbelt being provided with a plurality of perforatic-ns adapted to register above said'intervening spaces of said backing means as said feed-belt rides upon the same, and a work-holding member adapted to. engage.

said feed-belt by insertion in one of said perforations.

9. In a machine of the class described, a frame, a driving shaft, an a-brading means driven thereby, a work-supporting table, having a balanced vertical movement, means connected with said frame for adjustably supporting said table with relat-ion to said abiading means, means for transversely reciprocating said table connected through intermediatc nieelianism to said driving-shaft,

a feed-belt mounted in connection with said table, and means for driving said feed-belt also connected through said intermediate mechanism to said driving shaft.

10. In a machine of the class described, a frame, a driving shaft, an abrading means driven thereby, a. wOrk-supporting table, having a balanced vertical n'iovement, means connected with said frame for adjustably supporting said table with relation to said abrading means, n'ieaus for' transversely reciprocating said table connected through intermediate mechanism to said driving shaft, a feed-belt mounted in connection with said table, means for backing or supporting said feed-belt as it passes beneath said abrading means, a gravity presser-foot carried by said frame adapted to bebrought into contact. with said abrading means to hold the same yieldingly in contact with the work carried by said feed-belt, and means'for driving said feed-belt also connected through said intermediate mechanism to said driving shaft.

11. vIn a machine of the class described, a frame, a driving shaft, an abrading means driven thereby, a. work-supporting table beneath said abrading means, a bracket-ineinber at one end of said table, a driven shaft jonrnaled therein, a feed-belt pulley mounted on said driven shaft, another bracketmember at the opposite end of said table, a shaft carried thereby, au idler-pulley mounted on said shaft, a feed-belt ruiming over said feed-belt pulley and said idler-pulley,v

means for adjusting said idler-pulley to tension said feed-belt, and intermediate 'transmission mechanism connecting Said driven shaft with said driving shaft.

12. In a machine ot lthe character described, an abrasive element, inea-ns for holding said abrasive element yieldingly to its work, comprising a frame-work, a plurality of transversely extending presser-weights, means for pivotally connecting said presserweights to said frame-work to permit in each of the same an independent vertical play, and means for raising and lowering said frame-work to carry said presserweights away from'br into operative contact with said abrasive element.

13. Ina machine of theeharacter described, an abrasive element, means for holding said abrasive elenientylicldingly to its work, comprising a frame-work, a plurality of transversely extending presser-weights, means for pivotally connecting said presserweights to said frame-work to permit in each `of the saine an independent vertical play, means for raising and lowering said frame-work to carry ,said presser-weights away from or into operative contact with said abrasive element, and means connected with each presser-weight for engaging said frame-work to limit the downward swing'of vsaid presser-weights when said frame-work is raised away from said ab 'asive element.

14. In a machine of the class described, a frame, a hollow screw-threaded standard ad- 'justable in a portion of said frame, a tablebeam-backet provided with a shank slidably disposed in said hollow screw-threaded standard, a table-beam connected with said bracket, a work-supporting table supported in connection with said table-beam, counterbalancing mechanisms connected with each end of said table,'wher.\,by a balanced vertical movement of said table is provided, a work-feeding means carried by said table, and an abrading means supported in connec` tion with said frame above said Work-supporting table.

15. In a machine of the class described, a work-supporting table, a bracket-member at one end of said table, a driven shaft journaled therein, a feed-belt pulley mounted on said driven shaft, an adjustable bracketmember at the opposite end of said-table, a shaft carried thereby, an idler-pulley mounted onsaid shaft, and a feed-belt runningprising a track-piece in which said adjustl In testimony, that I claim the invention able bracket-member rides, a series of set forth above, I have hereunto set my hand ratchet teeth connected with said bracketl this 24th day of November, 1911.

member, and a pivotally mounted pawl for JOHN C. BLEVNEY.

' engaging said ratchet-teeth to hold said ad- Witnesses:

justable bracket-member in its adjusted po- Fmmii'.4 C. FRAENTZEL, I

sition. FREDK. I-I. W. FRAENTZEL. 

